org.apache.commons.imaging.internal.Util Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.imaging.internal;
import org.apache.commons.imaging.ImageFormat;
import org.apache.commons.imaging.ImageFormats;
import org.apache.commons.imaging.ImageParser;
import org.apache.commons.imaging.Imaging;
import org.apache.commons.imaging.common.bytesource.ByteSource;
import java.io.IOException;
import java.util.function.Predicate;
import java.util.function.Supplier;
/**
* Internal utilities.
*
* @since 1.0-alpha3
*/
public class Util {
private Util() {}
public static ImageParser getImageParser(ImageFormat format) {
return getImageParser((parser) -> parser.canAcceptType(format), () -> new IllegalArgumentException("Unknown Format: " + format));
}
public static ImageParser getImageParser(String fileExtension) {
return getImageParser((parser) -> parser.canAcceptExtension(fileExtension), () -> new IllegalArgumentException("Unknown Extension: " + fileExtension));
}
// This generics suppression is as good as the predicate given. If the predicate violates a generics design,
// then there will be an error during runtime.
private static ImageParser getImageParser(Predicate> pred, Supplier supplier) {
return (ImageParser) ImageParser
.getAllImageParsers()
.stream()
.filter(pred)
.findFirst()
.orElseThrow(supplier);
}
public static ImageParser getImageParser(final ByteSource byteSource) throws IOException {
// TODO: circular dependency between Imaging and internal Util class below.
final ImageFormat format = Imaging.guessFormat(byteSource);
if (!format.equals(ImageFormats.UNKNOWN)) {
return Util.getImageParser(format);
}
final String fileName = byteSource.getFileName();
if (fileName != null) {
return Util.getImageParser(fileName);
}
throw new IllegalArgumentException("Can't parse this format.");
}
}